In recent years, a child seat mounted on a seat of an automobile is used in order to protect a juvenile in the automobile against injury or mitigate the injury at the time of a traffic accident or the like by the automobile.
As a seat belt apparatus employed for this type of child seat, an end of a crotch webbing is fixed to the front center of a seat portion of the child seat and a buckle body is mounted on the other end of this crotch webbing, for example. Further, tongue members are mounted on webbings attached to extend over the right and left shoulders and the right and left hips of a juvenile sitting on the seat portion of the child seat respectively. It is so structured that the pair of tongue members are inserted into the buckle body thereby disengageably engaging with each other.
This type of disengageable buckle apparatus includes the one disclosed in Japanese Patent Application Laying-Open Gazette No. 8-70912, which has been brought into a structure comprising a pair of tongue members, an engaging member rotatably arranged in a buckle body for disengageably engaging with the respective tongue members, an ejector urged by an extrusion spring for urging the respective tongue members in a dissociative direction and a regulation plate inhibiting rotation of the engaging member in the engaging direction with respect to the tongue members when only one tongue member is inserted into the buckle body.
And it has been so structured that the regulation plate is rotated by the tongue member to inhibit rotation of the engaging member in the engaging direction so that no locked state resulting from engagement of the tongue member is attained when inserting only one tongue member into the buckle body and so structured that the regulation plate does not rotate but the engaging member engages with both tongue members so that an excellent locked state is attained when simultaneously inserting the pair of tongue members, to be brought into a structure aiming at improvement of reliability of the locked states on the side of the tongue members and the side of the buckle body.
According to the buckle apparatus disclosed in the aforementioned conventional gazette, however, it is a system separately comprising the rotatably supported regulation plate, and there has been such a defect that the number of components such as the regulation plate and a plurality of springs for setting the initial position of the regulation plate increases to result in a high cost.
Further, there has been such a problem that a space for rotating the regulation plate is also required to cause size increase of the overall apparatus and complication of the structure, and it is also inferior in assembling workability.